As the voltage increased, the puppy first barked, then jumped up and down, and finally started howling with pain. The volunteers were horrified. They paced back and forth, hyperventilated, and gestured with their hands to show the puppy where to stand. Many openly wept. Yet the majority of them, twenty out of twenty-six, kept pushing the shock button right up to the maximum voltage.

Intriguingly, the six students who refused to go on were all men. All thirteen women who participated in the experiment obeyed right up until the end.